Fuel controlling apparatus for longitudinally movable combustion chambers



1950 R. H. GODDARD 2,496,710

FUEL CONTROLLING APPARATUS FOR LONGITUDINALLY MOVABLE COMBUSTIONCHAMBERS Original Filed March 9, 1942 2 Sheets-Sheet l Feb. 7, 1950 R.H. GODDARD 2,496,710

FUEL CONTROLLING APPARATUS FOR LQNGITUDINALLY MOVABLE COMBUSTIONCHAMBERS Original Filed March 9, 1942 2 Sheets-Sheet 2 Patented Feb.1,1950 I UNITED sTAra FUEL CONTROLLING APPARATUS FOR LONGIIUDINALLYMOVABLE COM- BUSTION enemas 1mm 11. Goddard, deceased, late oiAnnapolis,

Mil, by Either C. Goddardyexecutrix, Paxtomf Mam, auignor oi one-half toThe Daniel and Florence Guggenheim Foundation, New York,

v N. Y., a corporation at New York.

application, March 9, 1942, Serial No.

ririnal 433,963, now Patent Nd. 2,397,658, dated April 2, i946. Dividedand this application February 2 Claims. (CL 60 35.6)

This application'is a division of original applia conical dischargeportion 21, and a discharge.

. cation Serial No. 433,963, filed by Robert H. Goddard March 9, 1942and issued April 2, 1946' as Patent No. 2,397,658. "This divisionalapplication relates more particularly to the mounting of the combustionchamber for longitudinal reaction and to the variation of the fuelfeed-in response to such axial movement.

This-invention relates to a combustion chamber in which mixed oxidizingand combustible gases or vapors may be continuously burned.

While capable of general application, this im-' proved combustionchamber is particularly de-" signed and adapted for use in thepropulsion of rockets or rocket crait.

An important object of thi'sinvention is to provide improved regulationof the fuel feed in a combustion chamber. In the preferred -form, fuelfeed is maintained in a definite relation to the axial displacement ofthe combustion chamber in its supporting structure, which displacementis related to changes in axial thrust produced by the combustion gasesin said chamber.

This invention further relates to arrangements and combinations of partswhich will be hereinafter described and more particularly pointed out inthe appended claims.

Preferred forms of the invention are shown in the drawings, in whichFig. 1 is a sectional front elevation of this improved combustionchamber: 7

Fig. 2 is an enlarged sectional front elevation of certain gasoline feeddevices for said chamber;

Fig. 3 is, a sectional plan view, taken along the irregular line 3-3 inFig. 2;

Fig. 4 is an enlarged detail sectional front elevation of an upperportion of the combustion chamber;

Fig. 4a is a slightly modified detail sectional plan view, taken alongthe line tar-4a in Fig. 4;

Fig. 4b is a fragmentary side elevation, looking in'the direction of thearrow 4b in Fig. 4a;

Fig. 5 is a detail sectional plan view of certain nozzle structure,taken along theline 5-5 in Fi 1;

Fig. 6 is a fragmentary sectional front elevation showing a bracedconstruction; and

Fig. 7 is a front elevation of a brace or bracket.

Referring to Fig. 1, a combustion chamber is shown comprising an innercasing 20, an intermediate casing or jacket 2|, and an outer casing 22,said parts being held in spaced relation by tie rods or braces 23 (Fig.4) secured to each of the casing members 20, 2i and 22.

.. 2 middle portion 25, a conical entrance portion 26,

nozzle 28. ,A liquid oxygen supply pipe to is connected into the spacell between the outer casing 22 and the intermediate casin or jacket 2!and adjacent the outer end of the nozzle 28. The space 3i is graduallyreduced in cross sectional area upward asvlewed in Fig. l and is closedat its upper end. This gradual reduction. in cross sectional areafacilitates the maintenance of uniform flow. The liquid oxygen isfurnished from any suitable supply under pressure. and the flow-ofliquid oxygen is controlled by a valve 32. I

The intermediate casing or jacket 2| isprovided with a multiplicityof-perforations 33 (Fig. 4) through which narrow streams or jets J ofliquid oxygen are projected against the outer surface of the innercasing 20 to'cool said inner casing and to prevent melting or burningthereof by the extremely hot combustion gases developed within thechamber.

Such narrow streams are superior to sprays for the reason that there isconsiderable friction tending to retard the motion of small drops, par-'ticularly in a gas of high pressure and density,

.which would reduce the speed, and hencethe The inner casing 20'comprises a cylindrical 66 cooling effect, of sprays.

In order to prevent rebound and scattering of the liquid as it engagesthe casing 20, recessed portions or dents 35 are provided in the casing20, which'recessedportions are convex inward and concave outward withrespect to the casing 20. The recessed portions 35- are aligned with thejets J and as each jet strikes one of these recessed portions insubstantial alignment therewith, the jet spreads out sidewise butdevelops enough centrifugal force to maintain the liquid in closeengagement with the casing surface, -so that the inner casing is thuseffectually cooled. The centrifugal force is strong because of the smallradius of curvature of the dents. Cooling is further facilitated by thecentrifugal force causing the liquid drops and cooler gas to makecontact with the wall.

Such engagement, besides cooling the casing wall at, also evaporates thecold liquid oxygen. The oxygen vapor or gas thus produced passes upwardalong the annular space 36 betweenthe walls 20 and 2| and enters thecombustion chamber as a conical sheet through an annular slot or opening38 (Fig. 4) at the top of the cylin-' drical portion 25 and just belowthe conical entrance portion 26. It will be noted that the annular space36 increases in cross section upwardly,

pinge from reverse directions, which causes very intimate mixture. Thegreater weight and volume of oxygen carries the gases well up in theentrance portion II, where mixing mainly takes place and where activecombustion is initiated.

In the lower conical portion 21 of the combusseparate recessed portionsor dents cannot be used, as they would break up the streamlined surfaceswhich are essential to prevent interference with the high velocitymovement of the combustion gases as they approach the nozzle 28 and aredischarged therethrough.

Consequently, in the portions 21 and 28 axially extending and outwardlyconcave ribbed portions are utilized, as shown at ll in Figs. 1 and 5.These ribbed portions develop the same centrifugal action in acircumferential direction as the dents 35 or "a but without interferencewith axial movement of the gases.

While it is necessary to cool the inner casing 20 to prevent destructionthereof, it is also desirable to prevent cooling of the gases in thecombustion chamber as frr as possible, and for this reason a thinrefractory lining 44 is provided within the parts 28 and 11 of thecombustion chamber and within the discharge nozzle 28.

This lining is preferably formed in relatively small sections or shellsandis of such thickness in relation to the thickness of the casing 20that the inner surface of the casing 20 is heated just below itssoftening point and that the inner surface of the lining N is similarlyheated just below its softening point. In this way, the casing 20 isprotected, while at the same time the combustion gases are maintained atthe highest permissible temperature.

Small shells a of refractory material are preferable because of thetendency of unequal expansion to produce cracks over large areas. In theform shown in Figs. 4a and 4b, the recessed portions or dents lib arequite close together and the shells of refractory material over thedents will be held in place by the arched or concave shape of thechamber wall.

A gasoline feed chamber ll (Fig. 2) is provided at the entrance end ofthe combustion chamber, to which gasoline may be supplied with valveopenings 58. The second or inner sleeve 64 is connected by a spider as(Figs. 2 and 3) to a supporting rod 5'! which is connected to a plate 58(Fig. l) which normally abuts the under side of a fixed frame member F.The upper end of the gasoline chamber 50 is connected by a bellowsmember I to the plate 58.

If the valve openings 53 and I! are aligned, in whole or in part,gasoline from the outer annular space 60 in the gasoline chamber 50 willpass through the valve openings 53 and 55 and thence downward throughthe inner casing 54 to a nozzle opening 62, provided with any usualdevice 83 for imparting a whirling motion to the gasoline as it is fedthrough the nozzle opening 62 to the upper portion 26 of the combustionchamber, which portion has a refractory lining N. Means for producingrelative axial motion be- .1 tion chamber and in the discharge nozzle28, the p tween the sleeves l2 and II will be hereinafter described.

The injected gasoline preferably forms a hollow cone of spray justinside the refractory lining 8|, this spray meeting the oxygen gasstream from the slot as at a substantial obtuse angle. The slot 3| isback of the refractory lining 64 and out of line with the gasolinespray, so that gasoline cannot enter the oxygen jacket 2| accidentally,in the absence of a high speed stream of oxygen gas, and thus produce anexplosive mixture when the oxygen starts to flow.

It will be noted by reference to Fig. 1 that the gasoline enters thecombustion chamber as a spray from the single nozzle opening 82. whereas1 the oiwgen enters the chamber almost entirely in gaseous condition andthrough the extended circumferential entrance slot 38. In order toimprove the mixture and to vaporize the gasoline as much as possible,special means are provided for heating the gasoline as it enters theportion It of the combustion chamber, such special means being necessaryin order to break up the gasoline into veryflnedrops in the relativelyshort available distance of travel. For this purpose. an annular passage65 is provided (Fig: 2) surrounding the discharge end of the gasolinechamber BI and connected by a bypass pipe 08 to the upper end of theannular oxygen space II. A shut-ofl valve I1 controls the flow throughthe pipe ll.

. For most efllcient operation, it is necessary that the proportions ofoxy en and gasoline be correctly maintained, and as variations in theamount of oxygen supplied unavoidably occur, due to changes in the rateof evaporation of the oxygen and to other variable causes, provision ismade to vary the gasoline feed with reference to variations in flow ofoxygen gas or vapor to the combustion chamber.

To accomplish this regulation, advantage is taken of the reactive eifectof the combustion gases issuing from the nozzle 28 against the closed orupper end of the combustion chamber 45 20. The more complete and perfectthe com? bustion, the stronger will be these reactive forces.

In order to utilize these forces in the regulation of the gasoline feed,the combustion chamber is mounted on an annular plate or ring I! 50(Fig. l) and a plurality of supporting rods I3 are provided, each ofwhich is secured to the ring I2 at its lower end. At its upper end, eachof the supporting rods 13 is connected to a chambered piston ll,slidable in a ilxed sleeve I and 5s pressed downward by a relativelystrong coil spring ll. Guide blocks 11 on the supporting rods I3 looselyengage the outer casing 22 of the combustion chamber and center thecasing but without exerting pressure thereon. to with the chamber. thussupported, the casings 20, II and 22 areunder tension, rather thancompression.- The reason for supporting the chamber and casings undertension rather than under compression is because all of these thin 68structures will withstand tension but not compression, except when theyare sustaining high internal gas pressure. Moreover, the thin refractoryshells a cannot withstand the bending which would accompany compression.Tension, 70 on the other hand, merely opens slightly th spaces betweenthe shells.

-. with this construction, any increase in the reactive forces from thename 28 will cause the chamber to move upward against the pressure is ofthe springs l0, carrying with it the gasoline chamber 50 and the outervalve sleeve 52. As the inner valve sleeve 54 normally remains fixed,the openings 53 and 55 will be more nearly aligned and the fiow ofgasoline will correspondingly increase. The flexible bellows member 59permits such relative upward movement of the gasoline chamber 50.

As the thrust increases. more gasoline will be admitted through theopening 55, and this will continue until the rate of gasoline flow issuch as to produce the greatest thrust for the oxygen fiow that istaking place. This oxygen flow, although mainly dependent on the amountof opening of the valve 32 (Fig. 1), also depends largely on thetemperature of the chamber and jacket walls. Further upward movement ofthe chamber 20 and gasoline chamber 50 will not increase the thrust,since the excess of gasoline over that required for best combustion willretard the oxygen fiow by creating extra chamber pressure. Thisretardation of the oxygen flow will reduce the combustion, and thevelocity of the gases from the nozzle will fall.

In order to prevent undesirable oscillations or "hunting of thecombustion chamber and particularly those produced by the coaction ofthe nozzle thrust acting on the valve 50 and the springs 85, perforatedpistons 80 are provided in cylindrical openings 8| in the pistons 14.These perforated pistons 80 are mounted at the lower ends of rods 83fixed in the frame F, so that a dash-pot effect is produced andoscillations of the combustion chamber are prevented. To permit upwardmovement of the oxygen feed pipe 30, a telescoping joint 84 (Fig. 1) isprovided.

It is desirable that the nozzle opening 62 at the bottom of the gasolinechamber 50 be positively closed when the apparatus is not in use. Forthis purpose, the plate 58 (Fig. 1) is mounted at the lower end of asleeve or plunger 86 slidable vertically in a bearing in the frame F andhaving a pin and slot connection 86a with a forked bell crank 81 andpull rod 88.

When combustion is to be discontinued, the rod Having thus described theinvention and the advantages thereof, it will be understood that theinvention is not to be limited to the details herein disclosed,otherwise than as set forth in the 5 claims, but that what is claimedis:

1. In a combustion apparatus, a fixed frame, a combustion chamber havingan axial discharge opening at one end, a supporting structure in whichsaid chamber is mounted for axial movement relative to said frame inresponse to changes in thrust produced by the flow of combustion gasesfrom said chamber, means to yieldingly resist such movement, means tocontinuously supply an oxidizing liquid under constant pressure to saidchamber, means to supply liquid fuel to said chamber, and valve means tovary the fuel flow in response to changes in the axial position of saidchamber relative to said frame.

In a combustion apparatus, a fixed frame, a

combustion chamber having an axial discharge opening at one end, asupporting structure in which said chamber is mounted for axial movementrelative to said frame in response to changes in thrust produced by theflow of combustion gases from said chamber, means to yieldingly resistsuch movement, means to continuously supply an oxidizing liquid underconstant pressure to said chamber, a first valve member adapted foraxial motion and radial flow and integral with said chamber, a secondvalve member attached to said fixed frame through a manually movableintermediate supporting device, said second valve member being freelyslidable along said first valve member and with which it coacts, abellows pack- ;;5 ing between said first valve member and saidintermediate device, and a third valve member integral with said secondvalve member and with said intermediate supporting device and tightlyclosable by axial movement therewith.

-10 ESTHER C. GODDARD,

Emecutrix of the Last Will and Testament of Robert H. Goddard, Deceased.

REFERENCES CITED I8 is pulled, depressing the sleeve 86 and forcinga'valve member 89 at the lower end of the rod 51 against the lower endof the gasoline chamber 50, thereby closing the nozzle opening 62. Theparts may be frictionally held in this position.

When active operation of the apparatus is to be resumed, the parts aremanually restored to the position shown in Fig. 1, which position willbe maintained during operation by friction and by the gaseous pressuresdeveloped in the apparatus.

As the parts adjacent the annular oxygen feed slot 88 are relativelyunsupported, brackets or braces 90 (Figs. 6 and '7) are provided whichare vertically disposed so that they do not interfere with the flow ofoxygen gas but which nevertheless firmly support the upper edge of theinner casing 20.

It will thus appear that simple and effective apparatus has beenprovided for cooling and continuously operating'a combustion chamber andfor automatically regulating the supply o fuel thereto.

The following references areofmord in the file of this patent:

UNITED STATES PATENTS Number Name Date 866,330 Calkins Sept. 17, 19071,291,032 Lesem Jan. 14, 1919 1,369,672 Koenig Feb. 22, 1921 1,820,154Peets Aug. 25, 1931 1,842,446 Dabrasky Jan. 26, 1932 1,929,778 GoddardOct. 10, 1933 2,103,274 Sanford Dec. 28, 1937 2,111,315 Damblanc Mar.15, 1938 FOREIGN PATENTS Number Country Date 625,104 France Apr. 19,1927 636,723 Germany Apr. 15, 1937 156,785 Switzerland Nov. 1, 1932'

